This invention relates to wooden handles for hand-held striking tools, particularly, to anti-slip wooden handles, especially hammer handles.
The user of a hammer or other hand-held striking tool desires that it be comfortable in use. The characteristics of the handle can contribute materially to comfort by, e.g., minimizing the transmission of vibration to the hand upon striking an object with the hammerhead.
Three materials commonly are used in hammer handles, namely, metal, fiberglass-reinforced plastic ("fiberglass"), and wood. The vibration-absorbing quality of metal and fiberglass is poor, so that they transmit vibrations relatively readily. To improve their vibration-absorbance, metal and fiberglass handles often are supplied commercially with rubber sheaths fitted over their gripping portions. Rubber sheaths also improve the anti-slip properties of the gripping portions. In some instances, these properties are further improved by providing holes or grooves in the surface of the sheaths.
Nevertheless, many carpenters and other craftsmen prefer plain wooden handles to those made of metal/rubber or fiberglass/rubber. Plain wood is perceived by them as being superior in vibration absorbance to handles made of the other-named materials, especially when the tools are used routinely for long periods of time.
Conventional wooden handles are smooth, so that the gripping portion of the handle affords relatively low frictional resistance to hand movement, or is relatively slippery, especially when aggravated by a film of perspiration from the hand. Economic reasons preclude manufacturers from improving the anti-slip properties of wooden handles by fitting them with the relatively expensive rubber sheaths, which, as a practical matter, are not reusable.
In the past, manufacturers of hammers with plain wooden handles have modified the surface of the gripping portions of the handles in several different ways to improve their slip resistance. Roughening coatings containing particulate matter have been applied to the gripping portion. A number of holes have been drilled into the surface of the gripping portion, or encircling grooves have been lathe-cut in the gripping portion. The modifications increase the roughness or friction afforded by the gripping portion, and, particularly in the case of the holes or grooves, provide reservoirs into which perspiration can drain from the surface of the gripping portion. However, they also increase the propensity of the handle to chafe or irritate the hand during use of the hammer.
A contributing factor in the case of the holes or grooves in the wooden handles is the presence of rough, broken, torn, or frayed wood fibers on the gripping portion at the edges of the holes or grooves. The broken fibers are a natural consequence of the drilling or lathe-cutting operations. Therefore, handles commercially modified in such ways are commonly employed only for a specialized procedure, such as where the tool generally is used only for short periods of time, and/or where the greatest possible anti-slip resistance is required because the slipperiness of the handle, or of the hand of the user, is increased by exposure to grease or oil.
Individual craftsmen in the past have modified the handles of their personal tools in ways similar to those used commercially, by drilling holes in the gripping portion, or by filing, grinding, or cutting grooves therein. Handles so modified also suffer from the irritation problems caused by rough, broken or severed fibers at the edges of the holes or grooves.